Railway traffic controlling apparatus



July 14, 1931.

G. WLBAUGHMAN RAILWAY TRAFFIC CIQONII'ROLLING APPARATUS Filed Feb. 19. 1931 I INVENTOR.

G BQU7/ mqn By cz-wm ATTORNEY.

Patented July 14, 1931 UNITED STATES PATENT- OFFICE GEORGE W. BAU'GI-IMAN, OF PITTSBTTRGH', PENNSYLVANIA, ASSIGNOR TO THE UNION or PENNSYLVANIA SWITCH & SIGNAL COMPANY, SWISSVALE, PENNSYLVANIA, A CORPORATION RAILWAY TRAFFIC CONTROLLING APPARATUS Application filed February 19, 1931. Serial No. 516,92 3.

My invention relates to railway traffic controlling apparatus, and particularly to automatic train control or cab signal systems of the coded continuous inductive type. More particularly my present invention relates to the trackway portion of systems of this character.

7 One feature of. my invention is the provision, in systems of this type, of means opera-ting when two consecutive track sections are occupied by trains and the forward train passes out of the forward section, to avoid any interruption of the supply of coded current to the rear section due to the time required for the track relay of the forward section to close its contacts.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic View showing one formof apparatus embodying my invention.

Referring to the drawing, the reference characters 1 and 1 designate the track rails of a stretch of railway track along which traflic. normally moves-in'the direct-ion in dicated by the arrow.- These rails are divided by insulated joints 2, to form a plurality of track sections, each-of which'may be similar to sectionqC-D shown in'the drawing. As here shown,-the railway is of the electric, propulsion type, and, consequently, the usual impedance bonds 18 are provided toqconduct the propulsion current around the insulated joints.

Located adjacent the entrance end of section C-D is a track relay E which, as here shown, is of the centrifugal type. Thisrelay comprises a rotor 3,, two stator windings 4 and 5, a. centrifugal device 6 operated by the rotor3, and a. contact 7 which is closed -when and only when the centrifugal device is rotating at or above a given speed. The stator winding 4 is connected across the rails 1 and 1*, and the other stator winding 5; is at times energized as hereinafter explained.

Located adjacent the exit. end of section C-D is atrack transformer F, the secondary8-t of which is? connected across the track rails, and the primary of which is energized at times as hereinafter explained. I

The track relay E controls a code relay in such manner that the code relayv is energized when and only when front contact 7 of relay E is closed. The circuit for relay G is from terminal X ofa suitable source of current, through contact 7 of relay E and the winding of relay G to terminal Yof the same source of current.

The code relay G controls a coding device H, which device comprises an operating winding 17, and two contacts 15 and 16 which are periodically closed at different rates when the winding 17 is energized.

The circuit for winding 17 is from terminal X, through the back point of contact 11 of relay G, and thewinding' 17 to terminal Y. It follows thatthe coding device H is normal'ly deenergized, but is set into operation when the coding relay G becomes deenergized'. The contact 16, when functioning.

transmits a caution code and may operate,

for example, at the rate of times per -m-inute. The contact 15, when functioning,

transmits a proceed code and may operate, for example, at the rate of times per minute.

Thecircuits for the primary of transformer F and the winding 5 of relay E may best be traced by explaining the operation of the apparatus, and this operation is as follows:

As shown in the drawing, sections CD and D"K are both unoccupied, so that relays E and E are both energized, with the result that code" relay G is energized and the coding device H is deenergized. Uninterrupted alternating current of normal voltage is being supplied to the track transformer primary 9, the circuit being from terminal X, through front point of contact 11 of relay G, primary 9, and the front point of contact 10 of relay G to terminal Y. VVindin-g' 5- of relay E is connected in multiple with primary 9 in this circuit. The right-handqterminal of primary 9; is also connected with terminal K, through front contact 12' of relay E but this fact isimmaterial.

I will now assume that a train moving toward the right enters section C-D. This will result in deenergizing relay E thereby opening the circuit for the code relay G at contact 7. The opening of relay G will open the circuit just traced for primary 9 and relay winding 5, and will also set the coding device H into operation. Alternating current will then be supplied to windings 9 and 5, the circuit being from terminal X, through front contact 12 of relay E windings 9 and 5, and a reactance 14 to terminal Y. The fact that the re actance 14 is now included in the circuit, will reduce the voltage applied to windings 9 and 5. l/Vindings 9 and 5 will be periodically placed on short circuit, however, because the left-hand terminal of winding 9 will be connected with terminal X each time that contact 15 of the coding device H closes. -The path for this connection is from terminal X, through contact 15, front contact 13 of relay E and the back point of contact 10 of relay G to windings 9 and 5. It follows that alternating current periodically interrupted at the rate of 180 times per minute will be supplied to the rails of section CD.

When the train enters section DK, it will open relay E thereby discontinuing the supply of alternating current to windings 9 and 5 through contact 12 of this relay. Alternating current periodically interrupted at the rate of 80 times per minute will then be supplied to windings 9 and 5, the circuit being from terminal X, through contact 16 of coding device H, windings 9 and 5 in multiple, and reactor 14L to ter minal Y. When the rear end of the train leaves section CD, the current thus supplied to windings 9 and 5 will energize relay E and this will result in energizing relay G, so that the operation of the coding device H will be discontinued. I will now assume that while the first train is in section DK, a second train enters section C D. This will again deenergize relays E and G, and will set the coding device H into operation again, with the result that the caution code will again be supplied to windings 9 and 5 through contact 16 of coding device H. If now the first train passes out of section DK, while the sec ond train still occupies section CD, track relay E will become energized, and being a centrifugal relay, it will require a brief interval of time for the front contacts of the relay to close. During this interval of time, however, transformer F will continue to be supplied with the caution code, and, consequently, there will be no interruption in the supply of code to the train which is occupying section CD The reason for this is, that the caution code current for the transformer F is not taken through a back contact of relay E and so there is no interruption to the supply of current to transformer F during the interval between the opening of the back contacts and the closing of the front contacts of this relay.

Furthermore, it will be noted that the coded current applied to the track transformer F is at a lower voltage than the track circuit current supplied to this transformer, thereby providing increased sensitivity in so far as concerns broken rail pro tection.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what i I claim is:

1. In combination, a rear and a forward section of railway track, a track circuit for the rear section comprising a track transformer and a track rela', a normally energized code relay for the rear section havin a circuit controlled by a front contact of the track relay, a normally deenergized coding device for the rear section set into operation when said code relay becomes deenergized and having a plurality of contacts operated at difierent rates, means operating when said code relay is energized to supply the primary of said track transformer with uninterrupted alternating current, means operating when said code relay is deenergized and the forward section is unoccupied to supply the primary of the track transformer with uninterrupted alternating current and for periodically placing such pri- 'mary on short circuit through a contact of said coding device, and means operating wvhen said code relay is deenergized and the forward section is occupied to supply the primary of the track transformer with periodically interrupted alternating current through another contact of said coding device.

2. In combination, a rear and a forward sect on Of'lilllWtLY track, a track c1rcu1t for the rear section comprising a track transformer and a track relay, a normally energized code relay for the rear section having a circuit controlled by a front contact of the track relay, a, normally deenergized coding device for the rear section set into operation when said code relay becomes deenergized and having. a plurality of contacts operated at different rates, means operating when said code relay is energized to 'su 9131 the )rimar of said track transl y l 15 former with uninterrupted alternating current at normal voltage, means operating when said code 'relay'is deenergized and the forward section is unoccupied to' supply the primary of the track transformer with alternating current at reduced voltage and for periodically placing such primary on short circuit through a contact of the coding device, and means operating when said code relay is deenergized and the forward section is occupied to supply the primary of said track transformer with periodically interrupted alternating current at reduced voltage through another contact of said coding device.

3. In combination, a rear and a forward section of railway track, a track circuit for the rear section including a track transformer and a track relay, means operating when said track relay is closed to supply the primary of said track transformer with uninterrupted alternating current, means op erating when said track relay is open and the forward section is unoccupied to supply the primary of said transformer with uninterrupted alternating current and for periodically placing said primary on short circuit at one rate, and means operating when said track relay is open and the forward section is occupied to supply the primary of said transformer with alternating current periodically interrupted at a clifferent rate.

4. In combination, a rear and a forward section of railway track, a track transformer having a secondar connected across the rails at the eXit end 0 said rear section, means operating when the rear section is unoccupied to supply uninterruped alternating current to the primary of said transformer, means operating when the rear section is occupied and the forward section is unoccupied to supply the primary of said transformer with alternating current and to periodically place said primary on short circuit to produce alternating current periodically interrupted at one rate in the rails of the rear section, and means operating when both of said sections are occupied to supply the primary of said transformer with alternaing current periodically interrupted at a different rate.

5. In combination, a rear and a forward section of railway track, a transformer having a secondary connected with the rails at the exit end of the rear section, means operating when the rear section is unoccupied to supply the primary of said transformer with uninterrupted alternating current at normal voltage, means operating whenthe I rear section is occupied and the forward section is unoccupied to supply the primary of said transformer with uninterruped alternating current at reduced voltage and for periodically placing said primary on short circuit to produce alternating current in the rails of the rear section periodically interrupted at one rate, and means operating when both of said sections are occupied to supply the primary of said transformer with alternating currentperiodically interrupted at a different rate.

6. In combination, a rear and a forward section of railway track, a centrifugal track relay having two windings the first of which is connected with the rails at the entrance end of the rear section, a track transformer having its secondary connected with the rails at the exit end of the rear section, means operating when said track relay is closed to supply the primary of said transformer and the second winding of said relay with uninterrupted alternating current at normal voltage, means operating when said relay is open and the forward section is unoccupied to supply the primary of said transformer and the second winding of said relay with uninterrupted alternating current at reduced voltage and for periodically placing said primary and second relay winding on short circuit at one rate, and means operating when said relay is open and the forward section is occupied to supply the transformer primary and the second winding of said relay with alternating current at reduced voltage periodically interrupted at a different rate.

7. In combination, a rear and a forward section of railway track, a track circuit for the rear section including a track transformer and a track relay, means operating when said track relay is closed to supply the primary of said transformer with uninterrupted alternating current at normal voltage, means operating when said track relay is open andthe forward section is unoccupied to supply the primary of said transformer with alternatingcurrent at reduced voltage and for periodically placing said primary on short circuit at one rate, and means operating when said track relay is open and the forward section is occupied to supply the primary of said transformer with alternating current at reduced voltage periodically interrupted at a differentrate.

In testimony whereof I affix my signature.

GEORGE W. BAUGHMAN. 

